Status and recent data of the
ANTARES Neutrino Telescope
Thomas Eberl
Erlangen Centre for Astroparticle Physics
for the ANTARES collaboration
TeV Particle Astrophysics workshop
SLAC, July 2009
The ANTARES Collaboration
23 institutes in 7 European countries
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
2
The ANTARES Collaboration
23 institutes in 7 European countries
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
3
The ANTARES Detector
~2m
Cable
ANTARES
2500m
depth
12 lines with 25 storeys each;
total of 885 PMTs
Completed 30-May-2008
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
A Storey: The Basic Detector Element
Local Control Module
(inside a titanium
cylinder)
Hydrophone RX
(5 per line)
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
Optical Beacon
(blue LEDs) for
timing calibration
(4 per line)
Optical Module:
17” glass sphere
10” PMT Ham. R7081-20
(14 stages)
High Energy Neutrino Detection Principle
p, a
3D PMT
array
nm
m
p
Cherenkov
light from m
Sea floor
nm
m
nm
interaction
m
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
43°
Time & position PMT
amplitudes:
of hits
m (~ n) trajectory
Energy
Background and Construction Progress
1 line
2 lines
5 lines
Single PMT rate
Precursor
line
10 lines
Full Antares
Cable Fault
2005
40K
2006
2007
decays and bioluminescent bacteria
(rate ~60 kHz)
2008
+ bursts from macroorganisms
Runs with high rate or large “burst fraction” fail quality cuts
High activity during spring 2006, 2009:
correlation with particularly cold winters?
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
2009
Muons
Detector footprint in muons
Detector as seen by atmospheric muons:
projection of fitted track position
at time of the first triggering hit
first 2 weeks of data
track seen on
minimum 3 lines
triggered hit:
high amplitude pulse
or
storey coincidence
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
(multi-) Muon Event
Example of a
reconstructed downgoing muon, detected
in all 12 detector
lines:
height
time
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
Depth Intensity Relation
Reconstructed tracks as a function of zenith angle:
 Use track length in water (“slant depth”)
30 days of livetime
Atmospheric muons
with E>20 GeV
Systematic uncertainties
shown:
Environmental and
alignment parameters
Track selection
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
EM showers in ANTARES
MMeasured Rate of muons
p producing N showers
5.6 days of data with
5-line detector
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
Neutrinos
Neutrino Candidate
z (height)
Example of a
reconstructed up-going muon
(i.e. a neutrino candidate)
detected in 6/12 detector lines:
time
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
Data 2007/2008 and Comparison to MC
5 lines (2007)
1.9 ×107 triggered events
Total : 245 days = 79% of calendar
Selected :168d = 69% of total
≥ 10 (9) lines (2008)
6.5 ×107 triggered events
Total : 242 days = 77% of calendar
Selected :173d = 71% of total
Neutrino Candidates
(after quality cuts):
Data:
MC:
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
1062 events
916 atmospheric neutrinos
40 atmospheric muons
ANTARES Neutrino Sky Map
5-Line Data (2007):
Require hits in at least 2 lines (to determine right ascension)
Additional quality cuts: Live time of 140 days
94 Neutrinos selected
(Equatorial coordinates)
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
Point Source Search
List of 25 sources for search:
3C 279
GC
Cent A
Galactic sources
Extragalactic sources
IC22 Hotspot
No significant excess in direction
of sources observed
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
Calculate neutrino flux limit:
ANTARES Neutrino Sky Map
Data of 2007 and 2008
750 “multi-line” Neutrinos selected
Data still blinded, positions are scrambled!
(Galactic coordinates)
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
Dark Matter Searches
χ
-ν
ν
5-line data, 68.4 days
(168 days × 0.51 Sun under horizon
× 0.8 trigger eff.)
No excess observed
Long term investigation necessary
(~3 years with 12 lines)
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
Multi Messenger Approaches
Gamma Ray Bursts (GRBs)
• GCN alerts trigger the recording of all low level triggers
• ~90% of GCN alerts are handled by ANTARES  9 TB of data
Fast Responding Robotic Optical Telescopes (TAROT)
• ANTARES alert: two events with ΔΩ < 3°x3°
in Δt < 15 min [rate(atm) = 0.05 yr-1]
• TAROT: two 25 cm telescopes at Calern
(France) and La Silla (Chile)
• FOV 1.86° x 1.86°
• ~10s repositioning after alert reception
• sending alerts since May 09
Gravitational Waves (Ligo/Geo600/Virgo)
• letter of intent prepared
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
20
The AMADEUS System of ANTARES
Goal: Feasibility study of acoustic detection techniques
n
hadronic
cascade
≈10m
≈1km
Expect bipolar pressure pulse:
• Taking data since 5-Dec-2007
En ~
> 100 PeV
fpeak = 10 ~ 20 kHz
• Completely installed since 30-May-2008
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
Direction Reconstruction of Acoustic Sources
Most probable
direction of source
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
Marine Sound Sources
S
W
N
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
Summary and Outlook
•
ANTARES was completed (12 detection lines) in May 2008
•
Muons under control: e.g. Depth intensity relation and
EM showers measured
•
More than 1000 upgoing events (neutrino candidates) have been
reconstructed (Jan 09)
•
First results from analysis with 5-line configuration
(search for point-like sources).
•
Multi messenger approaches pursued
•
ANTARES used as multidisciplinary platform
(e.g. acoustic neutrino detection)
Th. Eberl, University of Erlangen - ECAP, TeVPA, SLAC, July 2009
Backup Slides
Expected Performance (full detector)
Neutrino effective area
Angular resolution
Ndet=Aeff × Time × Flux
•For En<10 PeV, Aeff grows with energy
due to the increase of the interaction
cross section and the muon range.
•For En>10 PeV the Earth becomes
opaque to neutrinos.
•For En < 10 TeV, the angular resolution is
dominated by the n-m angle.
•For En > 10 TeV, the resolution is limited
by track reconstruction errors.
Acoustic detection of (U)HE ns
energy deposition in (hadronic) cascade
 bipolar pressure pulse in disc shape
hydrophone
array
n
cascade
acoustic
pressure
waves
Acoustic detector
• 3D array of hydrophones
• very long attenuation lengths
(of order 1km)
• medium: water, ice and salt
ANTARES angular resolution
Electronics simulation + light absorption & scattering
+ light background ( 40K + bioluminescence ~ 60 kHz ) :
Eµ >10 TeV
kinematics reconstruction
m
Angular resolution < 0.3°
n
WATER on ANTARES site
labs ~ 26/60 m @ 370/470 nm
leff (scattering) ~ 100/300 m @ 370/470 nm
Status: Detector complete since May 30, 2008
seismo
N 42°50’ N
IL07
6°10’E
L5
L2
L3
L4
L7
and
1 instrumentation line IL07
for the control of
environmental parameters
(e.g. sea current,
temperature, ...)
L1
L9
12 lines with 885 PMTs
L6
L8
L11
Submarine
cable
to shore
L10
L12
100 m
Junction box
29
Duration of lines in sea up to 3.5 y
L12
4
15
L11
4
33
L10
175
193
L09
174
L08
175
L07
175
L06
176
Installation status
2008/05/29
Connected
308
Deployed
327
421
441
L05
486
500
L04
486
507
L03
488
547
616
L02
672
819
835
L01
0
200
400
600
(days)
800
• Junction Box operational in deep sea since 6.5 years
• Line 1 works for more than 3 years
30
Cable Failure and Repair
•
Standard 40 km deep-sea telecommunications cable used to
connect shore station and junction box.
•
Cable failed in July 08, connection to detector was lost.
•
Investigations showed that sea water
had penetrated 100m into the cable.
•
Successful and standard repairing procedure
by France Telecom Ship 8 days ago!
ANTARES is back online
status of detector is unchanged.
Optical background rates
Dominated by 2 effects
40Ca
γ
1. b – decay of 40K
40K
γ
2. bioluminescent organisms
e.g.
32
Calibration with Potassium-40
40K
tuning 1
on average
~35 photons
coincidence rate during 18 months
tuning 2
Under investigation: PMT ageing?
Gain drop compensated by threshold tuning
40K
decay
(β or EC)
33
Acoustic positioning
Determination of line shape
and of module coordinates
every 2 minutes by
1. Acoustic triangulation
2. Compass data of storeys:
headings and tilts
25
20
14
8
1
•
Anchor with
transponder
34
Alignment with acoustic positioning
•
Hydrophone positions relative to line anchor
Storey 1
Storey 8
Storey 14
Storey 20
Storey 25
• Crucial to reach track
resolution < 1 degree
• Lines are floating with the
deep sea water current !
• Typical water speed:
a few cm/s
Necessary precision is reached
 positioning is under control
35
Detector status after cable repair
Floor nb
ONLINE CONTROL
~ 12% of channels
w/ low or w/o count rate
mostly power or
HV failure
2 sectors
(= 5 floors, red)
are unreachable
Line nb
36
Deployment
Connection
Nautile
(manned)
Victor
(ROV)
Pictures from the seabed
Detector layout
Point-like searches with 5 lines
•
No excess found, neither in the search within
the list of candidates nor in the all-sky search:
•
•
Significance of fluctuations:
•
1.6 (list of sources)
•
1.0  (all sky)
First limits have been set and are competitive
with previous multi-year experiments (with
only less than half of the detector and 140 of
live time!)
•
Blinding policy has been followed.
•
Paper with these results almost ready for
submission.
List of 25 sources
Region of sky observable by Neutrino
Telescopes
AMANDA/IceCube (South Pole)
ANTARES (43° North)
Mkn 421
Mkn 501
Mkn 501
CRAB
SS433
RX J1713.7-39
SS433
V. Bertin - CPPM ARENA'08 @ Roma
GX339-4
Galactic
Centre
CRAB
VELA
>100 GeV gamma skymap
Time calibration with LED beacons
•Four LED beacons/line
(with 36 blue LEDs
each) allow to illuminate
the neighbouring OMs
•Good technical
performance (45/47 are
working)
•Additional output: water
optical parameter
measurement
•Residual time offset grows
with distance (early photon
+ walk effect) according to a
straight  offsets measured
in the dark room before
deployment can be
corrected
•Checked with independent
K40 tests
σ = 0.4 ns
Electronics
contribution
less than 0.5 ns
Lines 1-10
DR - OB offset difference
RMS 0.7 ns
Only 15%
are larger
than 1 ns
Positioning
 Acoustic system:
 One emitter-receiver at
the bottom of each line
 Five receivers along
each line
 Four autonomous
transponders on
pyramidal basis
 Additional devices
provide independent
sound velocity
measurements
Measure every 2 min
-Distance line bases
to 5 storeys/line and
transpoders
-Headings and tilts
Positioning results
Comparison among storeys
Larger displacements
for upper top floor
Comparison among lines
Coherent movement
for all the lines of the
detector
Time residuals for point source analysis
Accumulated data
≥ 10 lines (2008)
19 ×106 μ triggers
65 ×106 μ triggers
5 lines (2007)
Cable repair
Total : 245 days = 79% of calendar
Selected :168d = 69% of total
Total : 242 days = 77% of calendar
Selected :173d = 71% of total
Data-MC comparison for downgoing events (5-lines)
data
CORSIKA
QGSJET +NSU
MC uncertainty
• No quality cuts applied
MUPAGE
data
CORSIKA
QGSJET +NSU
CORSIKA
QGSJET+Horandel
• Agreement within (substantial) theoretical
+ MC uncertainty
• Main experimental errors stem from OM
efficiency and acceptance and optical
water properties (λ abs λscatt)